Mobile Terminal and Corresponding Display Device with Associated Zooming Features

1. A mobile terminal, comprising: a first display unit configured to display a first screen image within a first content boundary, wherein the first display unit is a touchscreen; an interface unit configured to be connected to an external display device having a second display unit; a controller configured to: interface with the external display device and display a monitor window including a second screen image corresponding to the first screen image on the second display unit of the external display device, wherein the second screen image is displayed within a second content boundary and the first and second screen images are identical; in response to receiving a first touch input on the touchscreen of the mobile terminal, simultaneously: displaying a smaller range of the first screen image within the first content boundary displayed on the touchscreen of the mobile terminal by zooming in the first screen image; enlarging the monitor window displayed on the second display unit; enlarging the second content boundary of the second screen image; enlarging the second screen image displayed within the second content boundary while maintaining the range of the second screen image displayed within the second content boundary; and displaying a third content boundary within the second content boundary, wherein the third content boundary corresponds to the first content boundary of the zoomed in first screen image displayed on the touchscreen of the mobile terminal.

2. The mobile terminal of claim 1 , wherein the controller is further configured to, in response to receiving a second touch input on the touchscreen of the mobile terminal to zoom out the first screen image displayed on the touchscreen, control the external display device to enlarge the monitor window, display the enlarged monitor window on the second display unit of the external display device, and zoom out the second screen image in the enlarged monitor window.

3. The mobile terminal of claim 1 , wherein the controller is further configured to determine a strength of a connection communication signal between the mobile terminal and the external display device, and to control a size of the monitor window to vary in accordance with the determined strength of the connection communication signal between the mobile terminal and the external display device while the mobile terminal is connected to the external display device.

4. The mobile terminal of claim 1 , wherein the controller is further configured to turn off a power of the first display unit when there is no user input on the mobile terminal for a predetermined amount of time, and to control the second screen image to continue being displayed on the monitor window of the second display unit.

5. The mobile terminal of claim 1 , wherein the controller is further configured to turn off a power of the first display unit when there is no user input on the mobile terminal for a predetermined amount of time, and to control the monitor window to be displayed on the second display unit but not to display the second screen image within the monitor window on the second display unit.

6. The mobile terminal of claim 1 , wherein the controller is further configured to turn off a power of the first display unit when there is no user input on the mobile terminal for a predetermined amount of time, and to control the monitor window not to be displayed on the second display unit and not to display the second screen image in the monitor window.

7. The mobile terminal of claim 1 , wherein the controller is further configured to determine a prescribed event has occurred on the mobile terminal in a mute mode, and to control the monitor window to visually change.

8. The mobile terminal of claim 7 , wherein the controller is further configured to control the external display device to, in response to determining a prescribed event has occurred on the mobile terminal in a mute mode, vibrate the monitor window on the second display unit of the external display device.

9. A display device, comprising: an interface unit configured to be connected to a mobile terminal including a first display unit configured to display a first screen image within a first content boundary, wherein the first display unit is a touchscreen; and a controller configured to: interface with the external display device and display a monitor window including a second screen image corresponding to the first screen image on the second display unit of the external display device, wherein the second screen image is displayed within a second content boundary and the first and second screen images are identical; in response to receiving a first touch input on the touchscreen of the mobile terminal, simultaneously: displaying a smaller range of the first screen image within the first content boundary displayed on the touchscreen of the mobile terminal by zooming in the first screen image; enlarging the monitor window displayed on the second display unit; enlarging the second content boundary of the second screen image; enlarging the second screen image displayed within the second content boundary while maintaining the range of the second screen image displayed within the second content boundary; and displaying a third content boundary within the second content boundary, wherein the third content boundary corresponds to the first content boundary of the zoomed in first screen image displayed on the touchscreen of the mobile terminal.

10. The display device of claim 9 , wherein the controller is further configured to, in response to receiving a second touch input on the touchscreen of the mobile terminal to zoom out the first screen image displayed on the touchscreen, enlarge the monitor window, display the enlarged monitor window on the second display unit, and zoom out the second screen image in the enlarged monitor window.

11. The display device of claim 9 , wherein the controller is further configured to determine a strength of a connection communication signal between the display device and the mobile terminal, and to vary a size of the monitor window in accordance with the determined strength of the connection communication signal between the display device and the mobile terminal while the mobile terminal is connected to the external display device.

12. The display device of claim 9 , wherein the controller is further configured to continue displaying the second screen image on the monitor window of the second display unit, when a power of the first display unit is turned off after no user input has been performed on the mobile terminal for a predetermined amount of time.

13. The display device of claim 9 , wherein the controller is further configured to continue displaying the monitor window on the second display unit but not to display the second screen image within the monitor window on the second display unit, when a power of the first display unit is turned off after no user input has been performed on the mobile terminal for a predetermined amount of time.

14. The display device of claim 9 , wherein the controller is further configured not to display the monitor window and not to display the second screen image in the monitor window, when a power of the first display unit is turned off after no user input has been performed on the mobile terminal for a predetermined amount of time.

15. The display device of claim 9 , wherein the controller is further configured to visually change the monitor window, when a prescribed event has occurred on the mobile terminal in a mute mode.

16. A method of controlling a mobile terminal, the method comprising: displaying, via a first display unit on the mobile terminal, a first screen image within a first content boundary, wherein the first display unit is a touchscreen; connecting, via an interface unit on the mobile terminal, the mobile terminal to an external display device having a second display unit; interfacing, via a controller on the mobile terminal, the mobile terminal with the external display device to display a monitor window including a second screen image corresponding to the first screen image on the second display unit of the external display device, wherein the second screen image is displayed within a second content boundary and the first and second screen images are identical; and in response to receiving a first touch input on the touchscreen of the mobile terminal, simultaneously: displaying a smaller range of the first screen image within the first content boundary displayed on the touchscreen of the mobile terminal by zooming in the first screen image; enlarging the monitor window displayed on the second display unit; enlarging the second content boundary of the second screen image; enlarging the second screen image displayed within the second content boundary while maintaining the range of the second screen image displayed within the second content boundary; and displaying a third content boundary within the second content boundary, wherein the third content boundary corresponds to the first content boundary of the zoomed in first screen image displayed on the touchscreen of the mobile terminal.

17. A method of controlling a display device, the method comprising: interfacing, via an interface unit on the display device, with a mobile terminal including a first display unit configured to display a first screen image within a first content boundary, wherein the first display unit is a touchscreen; displaying, via a second display unit of the display device, a monitor window including a second screen image corresponding to the first screen image on the second display unit of the display device, wherein the second screen image is displayed within a second content boundary and the first and second screen images are identical; and in response to receiving a first touch input on the touchscreen of the mobile terminal, simultaneously: displaying a smaller range of the first screen image within the first content boundary displayed on the touchscreen of the mobile terminal by zooming in the first screen image; enlarging the monitor window displayed on the second display unit; enlarging the second content boundary of the second screen image; enlarging the second screen image displayed within the second content boundary while maintaining the range of the second screen image displayed within the second content boundary; and displaying a third content boundary within the second content boundary, wherein the third content boundary corresponds to the first content boundary of the zoomed in first screen image displayed on the touchscreen of the mobile terminal.